Crankshafts and connecting rods rotate at high-speeds during high engine loads, resulting in increased component temperatures along with increased axial and centrifugal forces being applied to the components. A hydrodynamic axial plain bearing may be used between the crankshaft and the connecting rod to provide lubrication to the components along with cooling. However, during certain thrust loads of the crankshaft, the hydrodynamic axial plain bearing may be insufficiently lubricate a gap between the hydrodynamic axial plain bearing and the crankshaft, resulting in metal-on-metal contact between the two, which may increase a likelihood of degradation.
Other attempts to address crankshaft lubrication include installing grooves and/or other grooves onto the hydrodynamic axial plain bearing. One example approach is shown by Chrestoff et al. in U.S. Pat. No. 5,829,338. Therein, a hydrodynamic axial plain bearing which has supporting surfaces configured such that a hydrodynamic lubricant film of a liquid lubricant can form in operation between the supporting surfaces and a bearing partner part. The supporting surfaces are here aligned parallel to corresponding supporting surfaces of the bearing partner part in a radial direction. Capture surfaces are mounted upstream thereof in the circumferential direction which are configured tilted to a normal on the supporting surface. This tilt lies in the circumferential direction. The purpose of these capture surfaces is to form a wedge-shaped gap to the bearing partner part in order to convey lubricant into a lubrication gap between the supporting surface and the bearing partner part on a relative movement of the hydrodynamic axial plain bearing relative to the bearing partner part.
However, the inventors herein have recognized potential issues with such systems. As one example, a lubricant path extends in a radial direction across an entire face of the hydrodynamic axial plain bearing. As a result, these paths are not constantly exposed to lubricant through a movement of the bearing and/or crankshaft. Thus, higher thrust loads may still result in metal-on-metal contact between the crankshaft and bearing.
The object of the present disclosure is to refine a hydrodynamic axial plain bearing such that a friction behavior and a wear behavior of the hydrodynamic axial plain bearing are improved further, also in relation to the bearing partner part. In a particular application, the axial friction contact between a connecting rod and a crankshaft is improved (e.g., decreased). Thus, the bearing may minimize wear and reduce friction between the bearing partner parts.
In one example, the issues described above may be addressed by a hydrodynamic axial plain bearing for supporting axial forces between bearing parts rotating relative to each other, comprising at least one supporting surface pointing in an axial direction towards one of the bearing parts, wherein viewed in a radial direction, the at least one supporting surface is arranged tilted to the radial direction, wherein the tilt is configured to form a lubrication gap, tapering radially towards the outside, between the supporting surface and the corresponding bearing part, wherein the supporting surface is part of an outer face of a connecting rod. In this way, friction between the connecting rod and the crankshaft is decreased due to the consistent lubrication provided by the bearing through a range of thrust loads of the crankshaft.
As one example, axial bearings are located on opposite sides of a bottom of a connecting rod where the connecting rod is coupled to a crankshaft. The axial bearings are ring-shaped with wedges and/or bevels configured to supply lubricant to a gap between the bearings and the crankshaft. The bevels face are located on surfaces of the bearings interfaced with the crankshaft along an entire circumference of the bearings. In one example, the bevels are differently angled to provide further lubrication while also mitigating a movement of the crankshaft due to varying thrust loads. Thus, an easy-to-design bearing may be installed on a plurality of connecting rods to decrease a likelihood of degradation to the connecting rod and/or the crankshaft.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.